HYMENOPTERA. 217 



legs. The antennae are generally filiform or setaceous, rarely clavate, 

 vibratile, and multiarticulated, being composed of sixteen joints at 

 least. In most of them the mandibles have no toolh en the inner 

 side, and terminate in a bifid point. The maxillary palpi, always 

 apparent or salient, consist most commonly of but five joints. The 

 ovipositor is formed of three threads. 



This tribe embraces almost the whole genus 

 Ichneumon, Lin* 



These Insects destroy the posterity of the Lepidoptera, so noxious 

 to the agriculturalist under the form of caterpillars, just as the quad- - 



ruped so called is said to destroy that of the Crocodile by breaking 

 its eggs, and even by introducing itself into the body of the animal, 

 in order to devour its entrails. 



Some authors have called them Mouches tripites, on account of the 

 three setae which compose their ovipositor, and Mouchei vihrantes, 

 because their antennse are continually vibrating. These organs are 

 frequently curled (contournees), and have a white or yellowish an- 

 nular spot in the middle. Tiieir maxillary palpi are elonpfated, 

 almost setaceous, and consist of from five to six joints; the labials v,/ 

 are shorter, filiform, and have but from three to four joints. The it f.y * 

 Jigula is usually entire or simply emarginated. The body is most QL t«L 

 frequently narrow and elongated or linear, Avith the ovipositor 

 sometimes exterior and resembling a tail, and sometimes very short j^ 



and concealed in the interior of the abdomen, which then terminates 

 in a point, whilst in those where the ovipositor is salient it is thicker, 

 and as if clavate and truncated posteriorly. Of the three pieces 

 which compose this instrument the intermediate is the only one 

 that penetrates into the bodies in which these Insects deposit their 

 eggs ; its extremity is flattened, and sometimes resembles tlie nib of 

 a pen. 



The females, anxious to lay, are continually flying or walking 

 about f, in order to discover the larvae, nymphs, and eggs of Insects, 

 and even Spiders, Aphides, &c., destined to receive their ova, and 

 when hatched, to sustain their off"spring. In this search they exhibit 

 a wonderful degree of instinct, which reveals to them the most secret 

 retreats of its objects. Those which are provided with a long ovipo- 

 sitor deposit the germs of their race in the fissures or holes of trees, 

 or under their bark. In this operation the ovipositor proper is intro- 

 duced almost perpendicularly, and is completely disengaged from its 

 semi-scabbards, which remain parallel to each other, and supported 

 in the air, in the line of the body. Those females in which the ovi- 



* This genus comprises upwards of twelve hundred species, and its study is ex- 

 tremely difficult. The labours of MM. Gravenhorst and Nees de Eseubeck have 

 rendered it somewhat easier. The former of these gentlemen has lately published 

 the prospectus of a complete work on these Insects, and we have every rea>on to 

 believe that this interesting portion of entomology will be henceforward as well un- 

 derstood as the state of the science will allow. 



■j- Some species are apterous or have but very short wings. They are the subject 

 of a particular Monograph, published by M. Gravenhorst, who has also furnished 

 us with another on the Ichneumons of Piemont. 



VOL. IV. Q 



